-- The smallest perimeter you can make with a certain area is a circle.
-- The NEXT smallest perimeter with the same area is a square.
With 1-ft by 1-ft square bricks, the shortest perimeter she could make would be by using her bricks to make it as square as possible. Without cutting bricks into pieces, the best she could do would be
-- Then, the more UNSQUARE you make it, the more perimeter it takes to enclose the same area. That means Mary has to make a rectangle as long and skinny as she can.
The longest perimeter she can make (without cutting bricks into pieces) is (39 bricks) x (1 brick) .
= (39-ft) x (1-ft) .
Perimeter = (2 x length) + (2 x width)
= (2 x 39-ft) + (2 x 1-ft)
= (78-ft) + (2-ft) = 80 feet .
What she'll have then is a brick path, 39 feet long and 1 foot wide, and when you walk on it, you'll need to try hard to avoid falling off because it's only 1 foot wide.
Well.. 160 x 3 = 480. So he would've had to give only 2 bags. But he would've given a fraction of a bag, but if you're only talking whole numbers, then the answer is 2. If you're talking fractions, then the answer is 2.51875.
